Radiation Laboratory last update, 30-April-2008 Location  Room 254/256, in the Main Research Building at RIKEN, Wako Address  Radiation Lab, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan Telephone  +81-48-467-9347 Fax +81-48-462-4641

The finest flexible print circuit board, for PHENIX Silicon Pixel Detector

Welcome to our home page.  The Radiation Laboratory is one of the eldest research group in RIKEN, now belonging to Nishina Center for Accelerator-Based Science. The major activity of Radiation Laboratory is to perform an experiment using high-energy polarized-proton collisions and heavy-ion collisions at BNL-RHIC in USA, through cooperations with RIKEN-BNL Research Center. We are also performing ion source developments and novel detector developments. On 1st of April 08, Y. Akiba is assign to be the experimental group leader of RIKEN-BNL Research Center. 

Our Activities

Spin Physics at RHIC		Heavy Ion Physics at BNL	Meson in Nuclear Matter
How the spin of proton is formed with 3 quarks and gluons? This is a very fundament question in QCD, Quantum Chromodynamic. The RHIC Spin Project has been established to solve this problem by colliding two polarized protons for the first time in history.   Collisions of polarized protons are measured with the PHENIX detector at RHIC.   PHENIX collaboration  Collaboration with accelerator group, theorists,  and other RHIC experiments is the key for the success of the program. The RBRC experimental group is conducting RSC, Rhic Spin Collaboration.	Research program is organized in PHENIX Spin Physics Working Group, and  analysis of the PHENIX data is performed at CCJ combined with RIKEN super computer cluster.   Recent analysis on the asymmetry of  the neutral pion production has shown that the gluon polarization in proton is surprisingly small, i.e. gluon is less likely  the career of proton spin.   Natural ansatz from this discovery is existence of significant orbital motion in the proton. Click above to enlarge	At RHIC QGP, Quark Gluon Plasma, should be created by colliding two gold nuclei, through which we can study the state of early Universe just after the Big Bang.    Very recently, enhanced e+e- pair yield above hadronic sources is observed in Au+Au collisions at RHIC. The characteristic temperature is determined to be 221 MeV.  This will be the key measurement to determine the nature of the hot and dens matter RHIC created.   Click above to get a preprint	While RHIC creates nuclear matter with high temperature, study of dense nuclear matter was being performed at KEK, and phi meson modification at normal nuclear density was discovered as shown  below. Click above to get a preprint  To extend our research further we proposed a new experiment to be done at J-PARC. Click above to get the proposal
QCD Theory	PHENIX Detector Upgrade	Laser Ion Source	Neutrons, optics and detection
Theory group in Radiation Laboratory is studying theoretical aspects of physics at RHIC. Our global analysis for world-wide asymmetry  data showed the  gluon polarization in proton is strongly constraneted with recent data from RHIC . Click above to get a preprint	To enhance physics capability of PHENIX even further, PHENIX Detector Upgrade R&D is on going through the collaboration with BNL instrumentation division, CERN-ALICE and CERN-NA60. 120 micron pitch wire bonding for Pixel Detector. Click Above to see the Ladder.	Developments of laser-induced plasma ion source is going as a collaboration with BNL Accelerator Division. This source ejects the world highest intensity of carbon and aluminum beam so far, and will be used for an ion injector for RHIC.  This method is so compact and can be useful for cancer therapy as well. RFQ used for the ion source	By combining novel methods for neutron optics with super conducting tunnel-junction detector, we aim to perform precise measurements for neutron decays. Applications go also to neutron interference and neutron scattering. Sextupole magnet to focus cold  neutron
Recent Memorial Events
Hiromi Okada, former Junior Research Associate of Radiation Lab., received RHIC & AGS thesis award 2007. R. Muto, former Special Doctral Fellow of Radiation Lab., received 2007 Young Scientist Award of the Physical Society of Japan. H En'yo and S. Yokkaichi received Significant Achievement Award in RIKEN, March 2008. Click above to go to  RIKEN Research Article	Five-year MoU between RIKEN and BNL was signed  by BNL Director S, Aronson and RIKEN President R. Noyori, Jan. 2007.	T. D. Lee, Director emeritus of RIKEN BNL Research Center  has awarded for The Order of the Rising Sun, Gold and Silver Star （旭日重光章）, Jan. 2007.	Phenix  event display was chosen for  RIKEN Art & Science Exhibition.

OUT REACHES ( in Japanese) サ イエンス・チャンネル The Brand-new Science NEWS ★ ファイ中間子の質量が高密度下で減少することを世界で初めて確認 サイエンス・チャンネル 未来を作る科学者達 ★ 素粒子クォークの仕組みを解明する サイエンス・チャンネル @mic go! go! 〜原子と原子核　基礎講座〜 ★ 素粒子 宇宙誕生100万分の1秒後の謎 （Ｊｉｐｐｉコンパク ト）